Headache, particularly migraine, is highly prevalent in patients with functional neurological disorder (FND) but is often underrecognized in clinical practice. This review provides an overview of the existing literature on the association between FND and headache and demonstrates that comorbid migraine is associated with greater disease severity and increased clinical complexity. FND and migraine may share, at least in part, common pathophysiological mechanisms. In clinical practice, careful attention should be paid to avoiding both underdiagnosis and overdiagnosis, and an integrated therapeutic approach is warranted.

This report describes the case of an 85-year-old male with a clinical phenotype consistent with pure autonomic failure (PAF) for more than four decades. Despite the presence of neurological manifestations, including bradykinesia, olfactory dysfunction, and visual hallucinations, phenoconversion to another α-synucleinopathy has not been confirmed based on established diagnostic criteria. Orthostatic and postprandial hypotension, low supine plasma norepinephrine levels, and reduced cardiac uptake on ¹²³I-metaiodobenzylguanidine myocardial scintigraphy were observed, consistent with the postganglionic cardiac sympathetic denervation frequently observed in Lewy body disease. Given the extraordinarily prolonged disease course and early central neurological signs, this condition may represent a preclinical stage of Parkinson’s disease or dementia with Lewy bodies. This case provides insight into the natural history of PAF and its clinical variability within the Lewy body disease spectrum.

A 64-year-old Japanese man presented with flu-like symptoms and received a diagnosis of COVID-19 (day 1). The patient developed sudden-onset involuntary movements in his trunk, left upper limb, and face (day 7). On examination (day 8), myoclonus was observed on the bilateral upper limbs and the trunk. Asterixis was also noted on the bilateral hands at the dorsiflex position of the wrists. Other neurological manifestations were unremarkable. After initiation of oral clonazepam (1.5 mg/day) administration, the involuntary movements vanished within several hours. No recurrence of the neurological symptoms, including any involuntary movements, was observed afterwards. Based on the clinical course, the patient was diagnosed with transient myoclonic state with asterixis (TMA) associated with COVID-19. Respiratory infections could cause TMA; however, there have been no clinical reports of TMA caused by COVID-19. Hypercytokinemia followed by COVID-19 and immune reaction against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can be related to transient dysfunction of the central nervous system, such as motor cortex, brain stem, and hypothalamus, which could be associated with development of TMA.

Duchenne and Becker muscular dystrophies are X-linked disorders that predominantly affect men; however, women can also develop symptomatic dystrophinopathy. We report a case of female dystrophinopathy characterized by childhood-onset motor difficulties, which evolved into slowly progressive, asymmetric muscle weakness in adulthood. The patient was a 79-year-old woman who had difficulty running since childhood but maintained independence in performing activities of daily living for many years. She began to experience gait difficulty at ~62 years of age, with gradually progressive muscle weakness that showed marked asymmetry. During initial evaluation at 68 years of age, skeletal muscle imaging revealed asymmetric muscle involvement suggestive of dystrophinopathy. A muscle biopsy demonstrated dystrophic changes; however, genetic testing was not performed at that time due to a lack of health insurance coverage. Thus, a definitive diagnosis could not be established. Upon further disease progression, the patient was re-evaluated at 79 years of age. On re-assessment, immunohistochemistry of the muscle biopsy revealed a mosaic pattern of dystrophin expression. Subsequent genetic analysis using multiplex ligation-dependent probe amplification identified a heterozygous deletion of exons 45–52 in the dystrophin gene that lead to an ultimate diagnosis of female dystrophinopathy. Clinical and radiological findings of asymmetric muscle distribution was considered characteristic of symptomatic female carriers. The clinical manifestations of dystrophinopathy in women are highly variable, and the absence of an apparent family history often contributes to a delayed diagnosis. The present case highlights the diagnostic challenges associated with female dystrophinopathy and underscores the importance of consideration of this condition in women presenting with progressive muscle weakness, particularly when marked asymmetry is evident. Early recognition and appropriate genetic testing are essential for establishing an accurate diagnosis, clinical management, and long-term follow-up, including surveillance for potential cardiac and central nervous system involvement.

A 69-year-old man presented with progressive cognitive decline over three months and two episodes of status epilepticus. Brain MRI revealed abnormal signals in the bilateral medial temporal lobes and deep white matter, and brain perfusion scintigraphy demonstrated increased perfusion in these regions. Electroencephalography showed sharp and slow-wave complexes with an F8 focus. Both serum and cerebrospinal fluid were positive for contactin-associated protein 2 (Caspr2) antibodies, and cerebrospinal fluid was positive for glial fibrillary acidic protein α (GFAPα) antibodies. Immunotherapy improved the clinical symptoms and MRI abnormalities, including deep white matter lesions. White matter involvement is rare in Caspr2 antibody-positive limbic encephalitis, and in this case, GFAPα antibodies may have contributed to the white matter lesions.

We report a case of unilateral relapsing primary CNS vasculitis (PCNSV) treated with Rituximab. A 52-year old man initially diagnosed as PCNSV by brain biopsy. He was treated with corticosteroids and no recurrence had been recognized for 4 years. However, after the reduction of corticosteroids to 9 mg, PCNSV recurred many times only in the right hemisphere. Mycophenolate mofetil and cyclophosphamide were not effective. We diagnosed this patient as unilateral relapsing PCNSV (UR-PCNSV), which is resistant to treatment and repeatedly relapses unilaterally. After rituximab was introduced, there was no clinical recurrence and abnormal lesions on head MRI improved. We emphasize that rituximab is a good candidate drug for treating the UR-PCNSV.

Bickerstaff’s brainstem encephalitis (BBE) is an autoimmune disorder typically localized to the brainstem. While cortical involvement is rare, severe cases presenting with decorticate posturing and profound consciousness disturbance can mask typical clinical features, making early diagnosis challenging. A 22-year-old woman developed progressive numbness in her limbs and lips, visual impairment, and impaired consciousness 13 days after an episode of gastroenteritis. Upon admission, she exhibited a Japan Coma Scale score of III-200, decorticate posturing, absent brainstem reflexes, and hyperreflexia. Cerebrospinal fluid analysis revealed pleocytosis and elevated protein levels. Although contrast-enhanced MRI showed only faint enhancement along the leptomeninges of the cerebral cortex and midbrain, acute-phase ¹²³I-IMP cerebral blood flow (CBF) single photon emission computed tomography (SPECT) demonstrated diffuse cortical hypoperfusion and paradoxical hyperperfusion in the bilateral basal ganglia. Furthermore, multiple autoantibodies associated with autoimmune encephalitis and demyelinating diseases—including anti-NMDAR, LGI1, CASPR2, AMPAR, GABABR, DPPX, GlyR, mGluR5, MOG, and AQP4 antibodies—were all negative in both serum and cerebrospinal fluid. Following aggressive immunotherapy, her consciousness improved rapidly. It was only during this recovery phase that the classic BBE triad of total ophthalmoplegia and ataxia became apparent, which had been masked by the initial severe consciousness disturbance. The diagnosis of BBE was retrospectively confirmed based on this clinical evolution and the high titers of serum anti-GQ1b and anti-GT1a IgG antibodies. Follow-up SPECT confirmed the normalization of CBF, correlating with her clinical recovery. This case demonstrates that cerebral perfusion SPECT is capable of detecting reversible dysfunction within the cortex and basal ganglia in BBE. It highlights the importance of considering BBE even in atypical cases with predominant cortical symptoms, where the diagnosis may only become clear through clinical evolution and ancillary functional imaging.

An 84-year-old woman presented with a two months history of progressive bilateral lower limb weakness and bladder bowel disfunction. Neurological examination revealed spastic paraplegia and anti HTLV-1 antibodies were positive in the serum and cerebrospinal fluid. Due to the rapid progression along with the elevation of neopterin and CXCL-10 in the cerebrospinal fluid, the diagnosis of rapidly progressive HTLV-1 associated myelopathy (HAM) was made. Chest X-ray and CT coincidentally revealed diffuse micronodular opacities, nodular in various sizes, and interlobular septal thickening. HTLV-1 associated bronchioalveolar disorder was the most likely diagnosis. Steroid therapy was effective against both spastic paraplegia and pulmonary lesions. Although the pulmonary lesions were identified incidentally in our case, screening for pulmonary lesions is important in patients with spastic paraplegia as it may lead to early diagnosis of HAM.